Device for tapping stay-bolt holes



(No Model.)

J. T. GONNBLLY. l DEVICE EUR TAPPING STAY BOLT HOLES. No. 443,234.

Patented Der;I 23, 1890.

@Dvi/mimmo LUNITED STATES PATENT Trice.

JAMES THOMAS OONNELLY, OF MILTON, PENNSYLVANIA.

DEVICE FORTAPPING STAY-BOLT HOLES.

SPECIFICATION forming part of Letters Patent No. 443,234, dated December 23, 1890.

Application filed October l5, 1890. Serial No. 368,187. (No model.)

' tain new and useful Improvements in Devices for Tapping Stay-Bolt Holes; and I do hereby declare that the following is a full, clear, and

exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to screw-tap devices for threading stay-bolt holes; and the object of my present invention is to provide a simple and improved device of this character which will be especially adapted for long distances-as, for instance, from the outer shell to the crown-sheet or from side to side of shell 1n locomotive-engines-and which will, furthermore, possess advantages in point of simplicity and inexpensiveness in construction, convenience and facility in use, ease and perfection of operation, and general efficiency.

To this end my invention consists in certain improvements in the class of tapping devices covered by my patent, No. 373,815, granted November 29, 1887; and my invention further consists in general features of construction and arrangement, substantially as will be hereinafter fully described, and particularly pointed out in the claims.

In the drawings, Figure lis a side elevation of my improved screw-tap devices for long distances. Fig. 2 is a longitudinal sectional view of the same. Fig. Sis an end view. Fig. 4. is a transverse sectional view on the line 0c as, Fig. 2. Fig. 5 is a transverse sectional view on the line y y, Fig. 2. Fig. o' is a transverse sectional view on the line .e z, Fig. 2. Fig. 7 is a side view of the spindle.

Corresponding parts in all the figures are denoted by the same letters of reference.

In my previous Letters Patent above noted I have shown a tubular screw-tap having a smooth bore which receives a corresponding smooth rod or spindle, upon which the tap is mounted and by which it is guided during operation. This construction and arrangement of tapping devices was especially adapted for use in cases where the stay-bolt holes are behind the frame of the boiler or locomotive, in which case the guide-rod was placed with its end against the inner face of the frame-work and the tap operating from the inside was guided by the rod and operated to tap the bolt-holes in both the inner and outer shells without removing the frame or otherwise disturbing the engine. This arrangement of tapping devices, while very effective under .usual conditions, is not particularly adapted for tapping stay-bolt holes in long distances, and my present improvements are therefore designed to provide an improved tapping device of the character set forth in my above-mentioned Letters Patent which will be especially adapted for convenient and effective operation under conditions involving long distances, and by the employment of which the operation of tapping can be more rapidly and economically accomplished.

Referring to the drawings, A designates two corresponding screw-taps provided with exterior threads ct, and having a central bore B, longitudinally disposed and preferably eX- tending entirely through the tap, this bore being threaded at o', as shown. The internally and externally threaded tubular screwtaps thus formed are provided with an angularouterenda for the application of a wrench, in the usual manner, and may be otherwise of any suitable or preferred construction.

C designates the spindle, which is externally threaded at c, to correspond to the threaded bore B of the taps. This spindle may be of any desired length, and upon it are mounted the screw-taps A A, one at either end, as shown, the taps being thus adapted to work upon the threaded spindle toward each other and be perfectly guided thereby. It .will be noticed that the spindle is threaded its entire length, and that the spindle, preferably, has the same pitch of thread as the taps, whereby the spindle serves to perfectly guide the taps in a straight line and effect a perfect relative operation as the threads are `cut in the respective bolt-holes.

In the manufacture and use of my improved tapping devices it will be noted that the taps can be made in various sizes, while the spin dles may be of uniform size, thus enabling taps of any size to be used and operated upon the sameesized spindle, and that the size of the taps is regulated by the diameter of bolt holes to be threaded, while the length of spin- IOO dle will be regulated by the longest distance between sheets, the diameter of the spindle being the same in any length of spindle or for any size of tap. A In the operation of the herein-described improved screw-tap devices forlong distances one of the taps is first screwed upon the spindle far enough to have a firm bearing. The spindle is then passed into the holes to be 1o threaded until the end of the tap enters the adjoining sheet, and the other end of the Ispindle extends or projects far enough from the hole in the other sheet to receive the other tap. The other tap is then screwed upon i5 this projecting end of the spindle, and the two taps are both run into the sheets and the bolt-holes threaded by the application of a wrencl1,in the usual manner. These improved devices are adapted to be used bytwo men at zo the same time, the devices being capable of simultaneous operation upon the bolt-holes in both sheets.

By reason of this improved construction and arrangement of internally and externally threaded taps mounted at opposite ends of a screw-threaded spindle having its threads of the same pitch as those of the taps7 it will be apparent to all those skilled in the art to which my invention appertains that 3o the taps are relatively guided in a perfectly straight line, even in tapping for long-distance holes, while the threads are perfectly cut in the walls of the bolt-holes in the respective sheets to exactly correspond one with the other and provide relatively perfectly threaded and centered holes for the reception of the stay-bolts.

Having thus described my invention, 1 claim and desire to secure by Letters Patent 4o of the United Statesl. An internally-threadcd screw-tap, substantially as and for the p urpose set forth.

A screw-tap having a central longitudinal bore threaded its entire length, substantially as and for the purpose set forth.

o. The combination, with a threaded spindle, of a screw-tap having a central bore and internally threaded, the internally-threaded screw-tap being adapted to work upon the screw-threaded spindle, substantially as and for the purpose set forth.

a. The combination, with a spindle threaded its entire length, of a screw-tap provided with a central longitudinal bore and internallythreaded its entire length, said internallythreaded tap being adapted to receive the threaded spindle and work upon the same, substantially as and for the purpose set forth.

5. In a device for tappinglong-distance staybolt holes, the combination, with a threaded spindle, of screw taps oppositely mounted upon the spindle and having a screw-threaded bore receiving the same, substantially as and for the purpose set forth.

(l. In a device for tapping long-distance staybolt holes, the combination, with a spindle screw-threaded throughout itslength, of screwtaps oppositely mounted upon the spindle and having a central longitudinal bore screwthreaded throughout its length and receiving the corresponding spindle, substantially as and for the purpose set forth.

7. In adeviee for tappinglong-distance staybolt holes, the combination, with the spindle threaded throughout its length, of screw-taps oppositely mounted upon the ends of the spindle and provided with a central longitudinal bore screw-threaded throughout its length, the threads of the spindle having the same pitch as the taps, substantially as and for the purpose set forth.

8. The combination, with a threaded spindle, of an internally and externally threaded screw-tap, substantially as and for the purpose set forth.

In testimony whereof I afiix my signature in presence of two witnesses.

JAMES THOMAS CONNELLY.

lVitnesses:

W. H. DIeKINsoN, II. E. Axcs'rnn'r. 

